Production of cyanamids and cyanids of the alkali metals.



APatented Oct. 15, 1912.

E. A. ASHGROFT.

APPLICATION FILED APR.15, 1911.

` PRODUCTION oF GYANAMIDS AND GYANIDS 0F THE ALKALI METALS.

'ing is a secification.

'reacting the alkali amid with `this invention a process fory the production with dicyandiamid or tricyantriamid, or other forms of cyanamid.

" UMTED STATES PATENT OFFICE EDGAR ARTHUR Asncnorm, or LONDON, ENQLAND. Pnoucmon or 'cYANnJs or THE ALKALI METALS.

Specification ofletters Patent. v l:Plagjented Oct. 15, 19912.

application mea apra 15, 1911. serial m. 621,391.

To all whom` it may concern: i

Be it known that I, EDGAR ARTHUR ASH- cnor'r, subject of the King of'England, ref siding in London, England, have invented certain new and useful Improvements in the Production of Cyanamids and Cyanids of the Alkali- Metals, of which the follow- The obf',ect of this invention is the economical production of cyanamids and cyanids of the alkali metals.

It is well known that cyanamids and cyanids are produced by reacting amids of the alkali metals (more particularly'sodium or potassium) with carbon lat suitable temperature's, the hydrogen escaping and-#the nitrogen of the amids remainingv in combinatlon as cyanamid or cyanid4 according to the' temperature and the amount of carbon employed. According to thisinvention cyanamid or cyanid of an alkali metal .is produced by dicyandiamid or tricyantriamid.

According to a modified process cyanamid or cyanid of an alkali metal is produced by reacting the alkali amid with dicyandiamid or` tricyant-riamid and the ammonia produced during the reaction is utilized for they production of the alkali amid.

`According to a further modification of ofA cyanamids and cyanids of the alkali metals4 consists in fusing the alkali metals In carrying the first part of this process into effect the following react-ion is utilized Similar reactions occur with tricyantriamid (or withl other forms of cyananiid) thereby roducing alkali cyanamid and am- .moniathe'latter beingused `again in they the reaction to fuse the product completely. y

When alkali cyanid is the desired end product the alkah cyanamid may be reacted.-

orf-the reactions may be combined thus and the temperature raisedl during the reaction to about 750L850 C.

In carrying out the above process the dicyandiamid or tricyantriamidare conveniently and economically obtained by' the known reactionof hot water on calcium cyanamid thus The calcium cyanamid as is well known is produced economically from atmospheric (4.)ana1Lciauz:Nazorg-tn2 thereby producing cyanamid of thevmetal and hydrogen which escapes. Sodium cyanamid maybe afterward converted to cyanid as described by the well known reaction with carbon."

i The preferred method of carrying this invention into effect will now be described with reference to the accompanying drawings, but it'.y is to be understood that the sequence of operations may be modified.

. The sodium amid isirst melted in a kettle A at a temperature which may begin at 150 C. The kettle is heated by the gas burners B. The dicyandiamid in dried crystallized form is slowly added to the melt by means of the hopper C and is stirred gently by the l stirrer D.- During the period of reaction, which may extend for some hours, the temperature is slowly raised until at the end of the treatment it reaches a point at `which the cya'namg productie fully fused viz:- about 60.0 If preferred the dicyandiamid,l which -is freely fusible at a very low temperature, Vmay be 'first melted in a closed vessel and poured. slowly into the melted amid with gentle stirring. During the Whole period of reaction the ammonia escapes from the vessel A by the conduit E and is collected.

As an example 78 kgs. of sodium amidis fused in the apparatus illustrated in the figure and 42 kgs. of dicyandiamid are added during two to four hours during which reaction takes place. 34 kgs. of ammonia escape and are collected. The product remaining is the cyanamid of sodium. The further treatment with 12 kgs. of carbon forv the production of cyanid' may be carried out in the same vessel or in another, after the previous reactions are completed, the temperature being suitably raised.

- 'In carrying into effect the second part of this invention the alkali metal would be melted in the kettle A. and the dicyandiamidwould be slowly added to the melt by means of the hopper C the mass being stirred gently by the stirrer D and heated until it forms 'a completely fused mass. The alkali metal reacts with the dicyandiamid to form cyanamid of the metal and hydrogen which escapes. Should cyanid of the metal be the required product carbon is mixed with the cyanamid in the kettle and the whole heated so that the carbon reacts with the cyanamid to form cyanid of the metal.

The herein described process, in 'conjunction with the manufacture off alkali amies from ammonia and alkali metals, or preferably by the direct process from sodium chlorid and ammonia, constitutes an advantageous method for the manufacture of cyanamids or cyanids of the alkali metals. The

ammonia in this combined process merely circulates and is not consumed, the nitrogen of the cyanid being 'supplied from atmospheric nitrogen. y

Although the process for the lproduction of cyanamid; or cyanid ofan alkali metal has been described as one in which the amid of the alkali metal or the alkali metal itself is reacted with dicyandiamid or tricyantriamid (the polymerized forms of pure cyanamid) these being the most stable practical forms of cyanamid, it will be evident that the unpolymerized form known tol chemists as cyanam-id (HgN-CN) can be employed when it can be obtained in stable form without departing from the invention aswell as still higher polymerized forms.

What I claim as my invention and desire to secure by Letters Patent is l. The herein described improvement in the process ofiproducing cyanamid of an alkali metal which consists in reacting upon the amid of said 4metal with a fform of cyanamid.

2. The herein described improvement in the process of producing cyanamid o-f analkali metal Which consists in reacting upon the amidof said metal with a form of cyanamid and utilizing the ammonia liberated by that reaction in the production ofan additional quantity of the alkali amid.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EDGAR ARTHUR ASI-ICROFT.

Witnesses:

HARRY B.- WIDGE, PERCY HEWI'rr. 

